The Curriculum for language and cognitive develpoment is based on our understanding of how students acquire concepts and language. Although educators used to believed that acquisition of literacy was based on the ability to master a sequence of readiness skills leading to beginning reading, the current understanding is that it is based on a cognitive developmental process. There are contrsting theories between cognitive development and language acquisition. Piaget(1973) believed that language is an ordinary cognitive process, dependent upon the cognitive processes for the course of its development. It clearly has cognitive precursors and prerequisites. It should follow the cognitive stages of development. Vygotsky(1978) proposed that speech and thought have different roots, speech has a pre-intellectual stage, whereas thought has a pre-linguistic stage. Up to some point in development, speech and language are independent. According to Vygotsky, when language and speech are connected: language and thought become interdependent, thought becomes verval, speech becomes rational. In comparison with two theories about cognition and language, Vygotsky believed that language and cognition originate independently but become interdependent, whereas Piaget believed that cognition determines language. It does not matter whether one advocates single view or a combination of two views of cognitive and language development. These views have a role of our understanding of ability to learn language